The present invention relates to a power controller, such as an inverter, for driving a compressor motor of a refrigerating system at variable speeds.
As power electronics has progressed recently, power controllers are employed in various fields. For instance, an inverter is used in a refrigerator and air cleaner for saving energy, and contributes greatly to energy saving of the apparatuses. The power controller has encountered a problem of how to dissipate heat from power elements, and various improvements have been carried out for the problem.
The Japanese Patent Laid-Open Publication No.09-283883 discloses a conventional power controller. FIG. 10 is a sectional view of the conventional power controller. Power converter 101 generates greater heat than the other components in the power controller. Large size radiator 102 is mounted to power converter 101 for dissipating the generated heat. First circuit board 103 is electrically connected to power converter 101, and mounted with smoothing capacitor 105 and voltage regulator 106 generating control-power-supply. First spacer 104 rigidly bonds radiator 102 to first circuit board 103. On second circuit board 107, controlling components such as a microprocessor (not shown) is mainly mounted. Second spacer 108 rigidly bonds first circuit board 103 to second circuit board 107. Cover 109 is mounted for covering these circuit components.
The conventional power controller discussed above has a problem that the controller itself has a large size. Particularly in a refrigerating system, e.g., a refrigerator, an available capacity of the system decreases as the power controller becomes large. The larger size controller requires a greater number of assembling steps to be assembled, and this increases a cost of the system.
In a power controller of the present invention, a controlling board is directly mounted to a compressor and thus, integrated with the compressor. CD This structure allows the controlling board to occupy a substantially less space.
A first board and second board bonded to each other with resin are directly mounted to a compressor. This structure allows the power controller to be reinforced and not to be affected by vibrations.
When a case of the power controller is mounted to the compressor, a temperature detector, which protects the compressor, is adheres to the compressor solidly and fixed to resilient supporting member. This structure reduces a number of steps for mounting a temperature protector to the compressor, and reduces a number of assembling steps to assemble the controller.
The second board being larger than the first board is prepared, and high-profile components to be mounted to the second board are placed around the first board. This arrangement can further slim down the power controller, and reduces substantially the capacity that the controller occupies.
An electrolytic capacitor is disposed on the second board, then a resin is flowed between the first and second boards until burying one third of the capacitor in height. The resin rigidly bonds the first and second boards. This structure not only further thins the power controller and reduces substantially the capacity that the controller occupies, but also reinforces the power controller, thus allowing the board to avoid being subject to vibrations.
The board, upon being directly mounted to the compressor, can downsize the controller. A case containing the controlling board, upon being mounted to a bracket of the compressor, can prevent a power-supplying pin from a weight stress and thus avoid the pin to be damaged.